Access Controller PCBA Electronic Assembly
In the process of PCBA electronic assembly production in Guangdong area, due to various companies' consideration of investment income such as equipment cost, revenue, depreciation, etc., low rate chip mounter is often used in SMT production.Bonding often uses table rotating ultrasonic welding machine;THT is often done by using manual plug-in and manual immersion tin stove.The impact of these hybrid assembly processes on PCBA design is as follows:
1. Single-sided or double sided arrangement of SMT components:
For a considerable number of plastic electronic products,their PCBA is mixed with three electronic assembly processes of smt,cob,THT. Therefore, it is very affordable to use these equipment and processes when designing single-sided SMT components, and the designer's products can be successfully completed.
When designing SMT components for double sided board mounting, three aspects should be considered: 1.As affected by SMT equipment, the number of components arranged on one side should be as small as possible. If no more than five, the production process should not be changed at high cost and no need to add solder paste with different melting points.The specific production method is as follows:
A. first, install the side of few part normally and finish the reflow welding.
B. Print solder paste on the other side,if using machine printing, need to adjust the position of back ejector;If manual printing, special clamps should be made to make the PCB flat to ensure solder paste printing quality.
C. After the assembly is done, place the PCB on the big aluminum plate for Bonding, enter the backflow welding machine, and properly lower the base temperature.
2. For the back of the Bonding naked IC, 20-30mm non-SMT components area need to be set aside to leave space for the table jig of Bonding machine (ordinary low-end Bonding machine is the table rotation, the back of naked IC must be aligned with the axis of the rotary table for good quality).
3. If plug-in components dipping tin is required, the thermal shock to SMT component will be over 200 degrees Celsius per second and SMT component will be damaged. At this point, should consider SMT component and THT component separately arranged in different sides of PCB.